Effect of the organochlorine pesticide endosulfan on GnRH and gonadotrope cell populations in fish larvae.

PIAZZA, Y.; PANDOLFI, M.; LO NOSTRO, F.

ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY

SPRINGER

Año: 2011 vol. 61 p. 300 - 310

0090-4341

Endocrine disrupting chemicals can influence the hypothalamus-pituitary-gonad axis and possibly affect reproduction in vertebrates. We analyzed the effect of 30-day endosulfan (ES) exposure in sexually undifferentiated larvae of the cichlid fish Cichlasoma dimerus. The number, area, mean cytoplasmic and nuclear diameter, and mean cytoplasmic optical density of gonadotropin-releasing hormone (GnRH) I, II and III immunoreactive (ir-) neurons and follicle-stimulating hormone (FSH) ir-cells were measured. Animals exposed to the highest ES concentration (0.1 µg/L) showed a decrease in GnRH I nucleus/cytoplasm area ratio upon exposure. Nuclear area and mean nuclear diameter of βFSH ir-cells was higher in ES treated fish. FSH nucleus/cytoplasm area ratio was high in exposed animals, and animals exposed to 0.1 µg/L ES showed smaller mean cytoplasmic optical density. These findings suggest that ES affects GnRH I and βFSH protein synthesis/release. However, these responses seem to be insufficient to affect gonadal differentiation at this stage of development.